HOUSTON -

Two commercial jets came dangerously close to each other Thursday night at Bush Intercontinental Airport.

A Singapore Airlines 777, a jumbo jet, flew within 200 feet vertically, and within about a half-mile horizontally of a Delta Airlines A320.

FAA rules require that aircraft remain separated by a half-mile vertically, and 3 miles horizontally.

"The pilot of the Singapore jet did not level off as required, causing a loss of required separation," Lynn Lunsford of the FAA said

The Singapore Airlines jet had just taken off. The Delta flight was on approach from Salt Lake City.

"Had they collided there would have been hundreds of deaths. It would have been a very large aviation catastrophe," Joshua Verde, a Houston-based aviation expert, told Local 2.

Verde reviewed the audio transmissions between the flight decks and Houston air traffic control.

"You can hear the stress in the (Delta) pilot's voice," Verde said.

It appears the Delta pilot was forced to take an evasive maneuver, diving several thousand feet in a minute, to steer clear of the larger jet.

The underlying cause of the close call is being investigated by the FAA.

IAH recently adopted new take-off and landing procedures, that are designed to be more efficient.

[Cockpit/Tower audio courtesy of LiveATC.net.]